We randomly assigned 4589 healthy nulliparous women who were 13 to 21 weeks pregnant to receive daily treatment with either 2 g of elemental calcium or placebo for the remainder of their pregnancies. Surveillance for preeclampsia was conducted by personnel unaware of treatment-group assignments, using standardized measurements of blood pressure and urinary protein excretion at uniformly scheduled prenatal visits, protocols for monitoring these measurements during the hospitalization for delivery, and reviews of medical records of unscsheduled outpatient visits and all hospitalizations. Calcium supplementation did not significantly reduce the incidence or severity of preeclampsia or delay its onset. Preeclampsia occurred in 158 of the 2295 women in the calcium group (6.9 percent) and 168 of the 2294 women in the placebo group (7.3 percent) (relative risk, 0.94; 95 percent confidence interval, 0.76 to 1.16). There were no significant differences between the two groups in the prevalence of pregnancy-associated hypertension without preeclampsia (15.3 percent vs. 17.3 percent) or of all hypertensive disorders (22.2 percent vs. 24.6 percent). The mean systolic and diastolic blood pressures during pregnancy were similar in both groups. Calcium did not reduce the numbers of preterm deliveries, small-for-gestational age births, or fetal and neonatal deaths; nor did it increase urolithiasis during pregnancy. Additional analyses utilizing the study database are being performed. During FY99 a manuscript on the relationship of glucose tolerance to preeclampsia risk was published in the American Journal of Obstetrics and Gynecology, another on resolving discrepancies between a meta- analysis and the CPEP trial was published in the JAMA, and two other manuscripts are currently in press at Obstet Gynecol: one on outcomes in healthy nulliparas who subsequently developed hypertension and the second on maternal calcium supplementation in relation to fetal bone mineralization. Laboratory specimens from the CPEP pilot study were used to assay cotinine and compare results with the results of smoking histories obtained at the same time. A manuscript on the accuracy of self-reported cigarette smoking amon pregnant women in the 1990s has been submitted for publication. Another manuscript on nutrient intake and hypertensive disorders of pregnancy has also been submitted for publication. Other studies are underway on the following topics: diet, ethnicity, and birthweight; urinary isoprostanes in severe preeclampsia; urinary kallikrein as an early indicator of preeclampsia; and urinary insulin in preeclampsia, gestational hypertension, and gestational diabetes mellitus. - calcium, preelampsia - Human Subjects & Human Subjects: Interview, Questionaires, or Surveys Only